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They came from 40 million BC

By Roger Lewin

FROM bees entombed in amber for up to 40 million years, US scientists have extracted bacterial spores and brought them back to life. The revived bacterium they identified has a relative that lives in the guts of modern bees and helps digestive processes.

The reanimation was the work of Raúl Cano and Monica Borucki of California Polytechnic State University in San Luis Obispo. They withdrew a tiny sample of the stomach contents of a bee entombed in amber from the Dominican Republic. They isolated bacterial spores from this material, and added them to a growth medium, where the bacterium started to reproduce (Science, vol 268, p 1060).

Cano and Borucki identified the bacterium by its shape and by the sequence of its ribosomal DNA. The sequence was similar to that of Bacillus sphaericus found in bees today. The differences can be explained by mutations over the past 25 to 40 million years.

Cano and his colleagues claim to have built up a menagerie of 1500 ancient microorganisms, including bacteria, fungi and yeast, over the past three and a half years. A few weeks ago they toasted their success with beer brewed from dinosaur-age yeast, which they dubbed Jurassic Amber Ale (the first batch is described as “pretty bad”, but there are hopes of better brews soon).

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The researchers say that their latest discovery should not arouse the same scepticism that met Cano’s claim for 135-million-year-old DNA in 1993. Many scientists suspected that biological molecules could not survive that long, and that the samples had been contaminated with modern DNA. However, Cano and Borucki say that in this case the tightly controlled conditions of isolation and growth, and the DNA analysis, should convince any sceptics that the bug is genuinely ancient.

According to Phillip Gerhardt of Michigan State University in East Lansing, Cano has succeeded. “There are dozens of claims in the literature for microbial spores surviving for hundreds, thousands or even millions of years,” says Gerhardt, an expert in the survival mechanisms of dormant organisms. “Cano’s is not only the oldest; it’s the best documented.”

The idea behind recreating past microbial worlds is to find new chemicals that might be useful to the pharmaceuticals industry. This is in the aim of Ambergene, a company set up in 1992 by Cano and Robin Steele, a biologist and lawyer. “The primary metabolism of these ancient organisms is similar to modern metabolism, so we can grow them,” Steele says. “But the secondary metabolism – the organisms’ chemical response to the environment – is very different, offering chemical novelty that’s hard to generate synthetically.”

Steele says that Ambergene scientists have already begun testing new chemicals from ancient organisms for antibacterial, antifungal and antitumour effects, with promising results.